During downhole exploration and formation excavation, a number of sensors and measurement devices may be used to characterize the downhole environment. Each measurement, or record of measurements, may be time-stamped, or associated with a known time, so that the measurements from the various devices may be processed together at the surface. However, each of the downhole measurement platforms operates with a respective local clock that is typically not synchronized with the surface master clock. Thus, before the various distributed measurements may be processed together, they must be synchronized to a common time. In prior systems, the surface processing system has undertaken the synchronization. For example, the master clock at the surface generates a synchronization signal, and the local clocks downhole use the signal to set their time in agreement with the master clock's time so that all time stamps are referenced to the same (master clock) time. As another example, the master clock generates a synchronization signal, and based on a response to that signal from each downhole device, the surface processing system stores a measured offset from the master clock for each device.